1. INVESTIGATION 3 BIG IDEA 1
Comparing DNA Sequences to Understand Evolutionary Relationships with BLAST
INVESTIGATION 3
BIG IDEA 1

2. Tutorials for BLAST at NCBI

3. The NCBI Handbook

4. BLAST Home Page

5. Student Investigation
Getting Started (pages S43 & S44)
Table 1: students construct a cladogram of the major plant groups.
Table 2: students construct a cladogram depicting evolutionary relationships among 5 species according to percent similarity.

6. Student Investigation
Team of scientists uncovered this fossil specimen in China.
Students make general observations about morphology and record those in lab notebook. (Page S44)

7. Student Investigation
Procedure (page S45)
STEP 1: Students form initial hypothesis as where they think the fossil specimen should be placed on the cladogram based on morphological observations made earlier.
Task is to use BLAST to determine most likely placement of fossil species in a cladogram
Based on DNA sequences extracted from tissue

8. Student Investigation
Procedure (page S45)
STEP 2: Students locate and download 3 gene files from Using Blogs In Science Education site.
Remind students that they cannot open files, but must upload to BLAST to view sequences.

9. Student Investigation
STEP 3: Students upload first gene sequence into BLAST by going to BLAST home page and clicking on “Saved Strategies” from menu at top of page.

10. BLAST Home Page

11. Uploading Gene Sequences
Click on “View” and upload a gene sequence. You cannot view the file on your computer.

12. Click on BLAST
Click on BLAST button at the bottom of the page.

13. Results
Click on a particular species to find out more specific information, including the classification scheme and the sequence of bases that appear to align with your gene of interest.

14. Results
Click on a particular species to find out more specific information, including the classification scheme and the sequence of bases that appear to align with your gene of interest.

15. Distance Tree of Results

16. The Cladogram

17. The Cladogram
This is a close-up of what you will see. Your gene of interest is highlighted in yellow.

18. The Cladogram
In addition, you will be provided with a “BLAST names color map” that looks like this so that you can better understand the cladogram your search produced.

19. What’s next? Students will
Repeat this process for 2 other genes of interest.
Analyze their results.
Decide whether or not the data from the BLAST search support their hypothesis about the placement of the fossil species on the cladogram.
Compare and discuss cladogram with other students.

20. Design and Conduct Investigation
Students will
Find and BLAST their own genes of interest.
Use example procedure provided.
Possibly use one or more of the suggested genes to explore. OR
use another source like SWAMI or ENSI before or after doing this lab.

21. SWAMI

22. SWAMI

23. ENSI